- Have received any of the following within 6 months of study entry: systemic corticosteroids; chemotherapy or radiation; erythropoietin, granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), or growth hormone; drugs that affect the immune system including thalidomide, interleukins, interferons, or other cytokines; anabolic steroids at high levels; or any experimental agent, unless allowed otherwise by the researchers.